Magnetically enhanced low temperature-high density plasma-chemical vapor deposition plasma source for depositing diamond and diamond-like films

Abstract

A magnetically enhanced low temperature high density plasma chemical vapor deposition (LT-HDP-CVD) source has a hollow cathode target and an anode, which form a gap. A cathode target magnet assembly forms magnetic field lines substantially perpendicular to the cathode surface. A gap magnet assembly forms a magnetic field in the gap that is coupled with the cathode target magnetic field. The magnetic field lines cross the pole piece electrode positioned in the gap. The pole piece is isolated from ground and can be connected to a voltage power supply. The pole piece can have negative, positive, floating, or RF electrical potentials. By controlling the duration, value, and sign of the electric potential on the pole piece, plasma ionization can be controlled. Feed gas flows through the gap between the hollow cathode and anode. The cathode can be connected to a pulse power or RF power supply, or cathode can be connected to both power supplies. The cathode target and substrate can be inductively grounded.

What is claimed is: 
     
       1. A magnetically enhanced plasma apparatus comprising:
 a hollow cathode target assembly; 
 an anode positioned on top of the hollow cathode target assembly, thereby forming a gap between the anode and the hollow cathode target assembly; 
 a cathode magnet assembly; 
 a row of magnets that generate a magnetic field in the gap and a magnetic field on a surface of the hollow cathode target assembly with the cathode magnet assembly such that magnetic field lines are substantially perpendicular to a surface of the hollow cathode target assembly; 
 an electrode positioned adjacent to the row of magnets behind the gap; 
 a pulse power supply coupled to the electrode; and 
 a radio frequency (RF) power supply coupled to the hollow cathode target assembly, the RF power supply igniting and sustaining plasma in the hollow cathode target assembly, a frequency and power of the RF power supply being selected to increase at least one of a degree of dissociation of feed gas molecules, degree of ionization of feed gas atoms, the pulse power supply generating a train of voltage pulses, a pulse, frequency, duration, and amplitude of the train of negative voltage pulses being selected to increase a degree of dissociation of feed gas molecules to form a layer from sputtering hollow cathode target material onto a substrate. 
 
     
     
       2. The apparatus defined by  claim 1 , wherein the RF power supply generates output voltage with a frequency in a range of about 1 MHz to 100 MHz. 
     
     
       3. The apparatus defined by  claim 1 , further comprising:
 a substrate holder; and 
 an RF substrate bias magnetically enhanced plasma power supply coupled to the substrate holder that generates a bias voltage on the substrate in a range of about −10 V to −2000 V. 
 
     
     
       4. The apparatus defined by  claim 3 , further comprising an inductor coupled between the substrate holder and ground. 
     
     
       5. The apparatus defined by  claim 1 , wherein the magnetic field in the gap is in a range of about 50 G to 5000 G. 
     
     
       6. The magnetically enhanced plasma apparatus as defined by  claim 1 , wherein the cathode magnetic assembly is rotatable. 
     
     
       7. The apparatus defined by  claim 1 , wherein the hollow cathode target assembly comprises at least one of B, C, Al, Si, P, S, Ga, Ge, As, Se, In, Sn, Sb, Te, I, Tl, Pb, Bi, Sc, Ti, Cr, Mn, Fe, Co, Ni, Cu, Zn, Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag, Cd, Lu, Hf, Ta, W, Re, Os, Ir, Pt, Au, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Be, Mg, Ca, Sr, Ba. 
     
     
       8. The apparatus defined by  claim 1 , wherein the hollow cathode target assembly comprises at least one of B, C, Al, Si, P, S, Ga, Ge, As, Se, In, Sn, Sb, Te, I, Tl, Pb, Bi, Sc, Ti, Cr, Mn, Fe, Co, Ni, Cu, Zn, Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag, Cd, Lu, Hf, Ta, W, Re, Os, Ir, Pt, Au, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Be, Mg, Ca, Sr, Ba in combination with at least one of the gases O 2 , N 2 , F, Cl, H 2 . 
     
     
       9. The apparatus defined by  claim 1 , wherein the pulse power supply generates voltage pulses with positive and negative portions. 
     
     
       10. The apparatus defined by  claim 1 , wherein the RF power supply generates output voltage with a frequency in a range of about 1 MHz to 100 MHz. 
     
     
       11. The apparatus defined by  claim 1 , wherein the RF power supply generates a negative bias voltage on the hollow cathode target assembly. 
     
     
       12. A method of sputtering a layer on a substrate using magnetically enhanced plasma, the method comprising:
 forming a gap between a hollow cathode target assembly and an anode on top of the hollow cathode target assembly; 
 generating a magnetic field in the gap such that magnetic field lines are substantially perpendicular to a surface of the hollow cathode target assembly; 
 connecting a pulse power supply to an electrode positioned behind the gap; 
 providing radio frequency (RF) power to the hollow cathode target assembly that ignites and sustains volume discharge in the hollow cathode target assembly; and 
 generating a train of voltage pulses comprising a frequency, duration, and amplitude selected to increase a degree of dissociation of feed gas molecules to form the layer from sputtering hollow cathode target material onto the substrate. 
 
     
     
       13. The method defined by  claim 12 , further comprising connecting an inductor between a pole piece and ground. 
     
     
       14. The method defined by  claim 12 , further comprising generating bias voltage on the substrate in a range of about −10 V to −2000 V. 
     
     
       15. The method defined by  claim 12 , wherein the magnetic field in the gap is in a range of about 50 G to 10000 G. 
     
     
       16. The method defined by  claim 12 , wherein the hollow cathode target assembly comprises at least one of B, C, Al, Si, P, S, Ga, Ge, As, Se, In, Sn, Sb, Te, I, Tl, Pb, Bi, Sc, Ti, Cr, Mn, Fe, Co, Ni, Cu, Zn, Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag, Cd, Lu, Hf, Ta, W, Re, Os, Ir, Pt, Au, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Be, Mg, Ca, Sr, Ba. 
     
     
       17. The method defined by  claim 12 , wherein the hollow cathode target assembly comprises at least one of B, C, Al, Si, P, S, Ga, Ge, As, Se, In, Sn, Sb, Te, I, Tl, Pb, Bi, Sc, Ti, Cr, Mn, Fe, Co, Ni, Cu, Zn, Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag, Cd, Lu, Hf, Ta, W, Re, Os, Ir, Pt, Au, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Be, Mg, Ca, Sr, Ba in combination with at least one of the gases O 2 , N 2 , F, Cl, H 2 . 
     
     
       18. The method defined by  claim 12 , wherein the pulse power supply generates voltage pulses with positive and negative portions. 
     
     
       19. The method defined by  claim 12 , wherein the RF power generates output voltage with a frequency in a range of about 1 MHz to 100 MHz. 
     
     
       20. The method defined by  claim 12 , wherein the RF power generates a negative bias voltage on the hollow cathode target assembly.